leaves dying curling. mg? burn?

White Widow
two plants
flowered for 8 weeks
5 gal Coir/Perlite 80/20
Canna Coco base plus Boost and Cannazym (every other feed) @ 5.8 pH on alternating feed/water schedule.
600w hps air cooled @ 1.5ft
temps at tops 82 degrees F
relative humidity 43-47 (fluctuates constantly)
supplement with CO2 in accordance with manufacturers directions


it started with leaf margin roll (like praying for mg) then light yellowing and progressed into what you see in the pics. 4 weeks ago i supplemented with PK 13/14. PPM spiked to over 2000. i flushed and went about business. margin roll started about this time. i assumed mg deficiency. supplemented accordingly, but it didn't do anything. assumed maybe root bound. yesterday i harvested and upon examining roots found no evidence of root bound. what do you guys think? burned them bad with PK and locked out mg? that's what i'm leaning towards, but i'd like other input.

thanks in advance.


here's how the symptoms present


71 tops total.


some look like this


others look like this

PPPPP- P burn, this is what happens when we try to feed to much bloom food to plants and then in an attempt to maximize yield. nice buds but can yu amagine if they hadn't of overdosed, did you try on occasion to correct the issue of lookout with mg? this looks like high doses of that too. The more I look, the more evidence of multiple overdose, seems to be present.

Which white widow was it? My Greenhouse ww did the same thing. I'd say p burn and mg def. If yours is like mine it burns mg super hard in flower, especially if you had 71 tops from two 5 gal containers. do 10 gals next time and i bet the problem is significantly reduced even if you don't alter the feeding regimen.

Mine are doing the same thing!
Ever since my PH meter broke,that is what mine turned into.
No matter what PPM i adjusted it to,they still curled up with dead ends and yellowing.
The last 4 grows were in soil,and did great till now,after my meter broke.
I wanted to buy a more expensive meter this time,but have not bought one yet.
I will order one tonight.

not sure of the genetics. just some clones i got from a friend who got them from a friend who got them from a friend etc. not even sure if they're legit. did not attempt to mitigate burn after first flush. burn did slow down after big flush (fortunately burn didn't begin until about a week from final flush.) plan on doing 15 gal this next time. shooting for 128 tops from two plants. will report. definitely check your pH, broski. it's imperative.